I could not sleep because it kept coming to my mind there should be an option in HourGlass to do rendering of the realtime audio output buffered in a thread…

This allows to get more stable playback when there are momentary spikes in the CPU load, at the cost of increased response time (latency) to parameter/envelope tweaks. There’s also a neat visual indicator of how well the buffering is doing. This isn’t quite public release ready yet, but will probably be included in the next version.